Magical Machine
by psychosocialwai
Summary: When Levi Ackerman entered Hanji Zoe's laboratory to bring a sample of Eren's titan form's hardening remains, he curiously entered a glass door but he found himself in a completely different world. Canon Universe/Alternate Universe
1. Chapter 1

**OVERVIEW**

When Levi Ackerman entered Hanji Zoe's laboratory to bring a sample of Eren's titan form's hardening remains, he curiously entered a glass door but he found himself in a completely different world. _Canon Universe/Alternate Universe_

* * *

 **ABOUT**

 _Post-Expedition to Shiganshina and the retake of Wall Maria (CU/AU); in which_ ㅡ

 _Eren Jaeger already mastered his titan form's hardening ability,_

 _Dead Survey Corps members and canonical characters are still dead,_

 _Historia Reiss is queen,_

 _& Levi Ackerman and the eight remaining Survey Corps survivors finally went to the ocean._

* * *

 **WARNINGS**

 _Contains spoilers_

 _Reincarnation_

 _Swearing (which is a normal thing because Levi, you know)_

* * *

 **DISCLAIMER**

All canonical characters and references of Shingeki no Kyojin are owned by Isayama Hajime.

* * *

 **CHAPTER ONE**

"Good morning, Captain!"

She would never get tired of greeting him every day. Before going to work, she would always take time to have a short chat with him. It has been her daily morning routine.

She tucked her long fringe behind one ear to see him better. "I hope to see you in my dream again tonight." A faint smile suddenly curved her lips while staring at him. "It feels so real."

An impatient knock distracted her from recalling her seemingly real dream. "Petra, we're gonna be late!" Someone called on the other side of the door.

She quickly looked to where the voice came and replied, "Five seconds, Nifa!" Then, she turned back and said, "I have to go, Corporal. Don't worry, I won't mess up today."

She chuckled sheepishly with a sudden inward cringe. She saluted before the wall and leaved her bedroom. When she reached the living room, she saw Nifa standing by the wooden double doors.

"Come on." she impatiently waved a hand, gesturing her to hurry up. They still have to walk through the long corridors and aisles by the foyer like the usual.

"Alright, let's go." Petra said after grabbing her handbag and keys.

They made sure that the doors and windows were tightly locked before leaving. They have acquired slight feelings of paranoia on thieves since three men broke inside last month. When everything was sure safe, they started walking across the grand foyer, carefully keeping their heels tight downstairs going to the aisle near the garden, and finally reaching the area where they had always been parking their carsㅡthe garage located in the back.

Their apartment was an old manor owned by an old veteran couple who was now living far from the capital. They were only paying for water and electricity bills because the couple just wanted some people to live there rather than be dwelled by ghosts. At first, they wanted to decline the offer but after some tough decisions they decided to grab the opportunity. Unlike Nifa, Petra took a year to adjust before she finally realized that the apartment they found was an extraordinary house of two among the few soldiers who survived the world war.

"Are you talking to your military painting boyfriend again?" Nifa asked with a slight scowl on her face.

Petra chuckled as they were walking together on the garage. "Always."

Nifa snorted. "Isn't he a bit stiff to talk with?"

"He is but it doesn't matter. He never complains on my stories." she replied while cheerfully playing the car key on her index finger as she headed towards her white car.

"Of course he won't. Try removing the glass that you put on the frame, you might hear him speak." Nifa said sarcastically. "Your three-year delusion is creeping me out." she added, walked ahead and jabbed the key on her black car. "See you on my office later."

Petra faltered before opening the driver's door and looked at her, blinking. "Why?" she asked curiously.

"You need counseling." Nifa answered with a grin.

Petra opened the driver's door and with a small laugh, she said, "I thought dual relationship is not allowed in counseling."

Nifa just shook her head with a curve on her lips and went inside her car. She was not against her friend's admiration; she was just finding it weird for a young university physician to talk and fangirl so bad over a painting every day. It has been three years since they moved there and though she really found it odd, she decided to just ride on her gig anyway.

* * *

"Floch, have you seen Hanji-san?" Eren asked casually when he caught sight of his comrade on the corridor. He halted behind Floch and took a swift glance by the window, hoping to see her outside the headquarters.

Floch turned to face him. "I also can't find her since morning."

"How about Levi Heichou?" Eren's jade orbs were expectantly waiting for a more reliable answer.

"I noticed him cleaning his old squad's barracks earlier but he's not around this afternoon either." Floched answered, an exasperated sigh followed his response.

"I see." There was a hint of disappointment on Eren's face.

"Why are you looking for them, Eren?" Floch asked suspiciously.

Eren shrugged. "I just…need to tell them something important."

"I see." Floch breathed and clapped a hand on Eren's shoulder before leaving.

Eren sighed and leaned his back on the wall. His mind was boggled by some things he couldn't tell to Armin and Mikasa. He considered to report it to his superiors but they were not around, strangely. Before his mind could fly further, he was distracted by Sasha and Connie's laugh outside the headquarters, it looked like they were teasing Jean, so he started to walk towards the exit to join them. But before reaching the door, the next thing that caught his attention was the sudden crash that he heard from the distanceーHanji's laboratory.

* * *

"Shit."

Levi swore under his breath after unexpectedly crashing from something like a hard, transparent, thin wall. Scattered pieces of glass gave him tiny cuts in his arms when he covered his face from his sudden fall. His hand pressed a soft, comfortable surface that he has dived in; for a short while he figured out that it's a bedㅡtoo huge and more comfortable than those in the barracks. Behind him was a framed painting of the sacred wall where he thought the broken glass came from. A realization hit him that gave an idea of what the hard, transparent, thin wall wasㅡa glass frame. He stared at the painting and noticed that there was missing on the perspective. He suddenly recalled something that brought a big question mark in his head; he came out of that big, glass-framed painting and he didn't know how it happened. He cursed again.

When he looked around him, he caught sight of his reflectionーit's a clear, wide mirror across the bed where he was sitting. Settled on top of the cabinet beside the mirror were stuff that looked like cosmetics that he used to see on every female soldiers' barracks (except Hanji's) when he was on cleaning duty. He winced on the items for a moment, reminding himself of someone, then shifted his sight on a small picture frame hanging on the wall. He walked towards it to see better and a curse rolled out of his tongue for the third time when he stared on the two people posed cheerfully.

"Where the hell am I?" he asked himself with a harried look on his face. "If this is Eldia or Marley, I'm going to kick their damn asses off."

He continuously searched the room and found some piles of paper on a small table near the bed, an empty mug of coffee settled beside it. Before he could get and read what has been written on the first page, a thin, hand-sized rectangular thing on top of it almost gave him a mini-heart attack. He realized he was not wearing his 3D Maneuver Gear so he would use hand combat if needed and prepared himself for something dangerous; he immediately stepped backwards. The thing just kept on producing an odd sound and an image appeared on the surface. It has something that was written on it but he couldn't read it. It's different from their alphabet. The face on the image behind the letters was very familiar.

"What is that thing?" he asked as if talking to someone while glowering at the thing from the distance that was about a meter away from him.

After several seconds, the odd sound stopped and the image on the surface faded to black. He sighed and looked back at the painting near him.

"I need to get back."


	2. Chapter 2 : Part One

**CHAPTER TWO**

(Part One)

THREE YEARS AGO

"Wait, what exactly are you saying?"

There was a chuckle on the other line while Petra tightly hugged her grumpy bunny stuffed toy in military costume.

"Pack your stuffs tonight because we're going to the capital tomorrow. We're hired!" Nifa excitedly announced over the phone.

"Are you serious?!" Petra exclaimed in surprise, jumping off her bed and throwing the stuffed toy on the corner.

"Yes! I'm serious! They already sent an e-mail, haven't you read it yet?" Nifa replied and they both screamed in excitement.

Outside Petra's room, her father was listening to the noises she was creating and she realized how loud her screams must be.

She checked her e-mail and read that they were asked to report the day after tomorrow. "I'm gonna tell it to Papa. Good night." She told Nifa after confirming the good news and hanged up.

She ran to open the door just to find her father standing in front of it.

"What happened? Why are you screaming?" He asked worriedly.

She gave him a tight hug and said, "I'm hired, Papa!"

Her father was confused. "Hired? To where?" He asked, eyebrows were twitching in curiosity.

She loosen the hug and said, "Remember the university that me and Nifa had applied last week? They are asking us to report the day after tomorrow. I was hired as the university physician!"

"We should celebrate tonight then." He said with a smile and grabbed the keys.

It was dinner time so instead of preparing something to eat, they decided to spend their dinner in a classy restaurant in town. They were living a simple life in the outskirts of the capital, almost near the rural areas, and the nearby town was several kilometers away from their house.

Petra was grateful that they've got time to spend dinner together before she went to the capital. She knew that she would be leaving him alone when she started to work as a university professor.

Days passed like a blink of an eye. She was both excited and sad. That would be the first time that she would leave her father but she wanted to pursue her dream of working and practicing her chosen career. Her father never got tired of supporting her dreams and he was so proud of her.

"Papa, will you be alright?" She asked him before she opened the passenger seat's door.

Her father drove her to the capital to ensure her safety. They parked in front of the building that Nifa told her to be their meeting place.

He smiled and stroked her hair. "I'll be fine, honey. Don't worry about me."

She hugged him tight and said, "Don't forget to drink your medicines. Take care of yourself and the goats."

Knowing that his father was getting old, an old fashioned-man, didn't know how to use the internet, and has hypertension, she promised him that she would call on the telephone every weekend. Before the tears that she'd been controlling since last night could flow from her eyes, she stepped out of the car and faced the tall and huge buildings of the capital. After a short melodramatic fairwell, her father went off.

Before she could pick her phone to call her friend, a very familiar voice called out her name that made the people passing by to look at them. Nifa was running with open arms, the handbag hanging on her shoulder was swaying in the air.

"Nifa." She said and returned the hug.

"Let's go?" She asked, thumbing over her shoulder a hotel. "We have to check in for a while."

After they put their luggages on the hotel room, they went to look for an apartment near the university.

"Don't they have cheap apartment rentals here?" Nifa muttered as they were walking dejectedly by the street.

Their search for a cheap apartment was in vain. Aside from that, the apartments near the university were already occupied.

"Where are we going to live?" Nifa mumbled as they stopped in front of a convenient store near the hospital.

Petra shook her head hopelessly.

"You kids should back off before I break your ribs!"

Their attention was caught by an old woman being surrounded by three boys who seemed to be college students.

"Shut up and give us your money!" One of the boys yelled before the old woman's face and it made Petra furious.

She crossed the street and confronted the boys that surprised the old woman. Nifa followed her.

"Hey, you!" Petra confronted the one who yelled before the old woman. "Don't you have respect to the elderly? You should apologize!"

The three boys looked at each other and laughed out loud.

"What are you saying, lady? We are not disrespecting her. We're just asking for money. Nobody needs an apology." The boy replied with a sarcastic grin.

She clenched her fist in anger, but before she could say a word, the old woman spoke.

"If another war rises in this generation, I don't know if these kids will make it alive." She said and grabbed the back of the shirt of one of the boys. "Next time, know who you ask for money." She added and threw the boy on the ground, as if she was used to fights. She was strong than Petra has even expected.

"You old ha-" the other boy was interrupted when a strong fist punched him in the face that made him fall to the ground.

Petra was surprised to see a grumpy old man standing before them.

"I always believed that pain is the only way to discipline brats." The old man said and beat the three boys.

Petra and Nifa couldn't react to what they had witnessed. Those old people were seemed to be experts in hand combat and were strong despite their ages. When the old man was done beating the three boys and has called the policemen, the old woman thanked Petra for confronting the boys.

"It's nothing. I am not of any help." Petra said sheepishly.

It was an awkward one minute of her life when she noticed that they were staring at her face intently.

To cut the awkward air that was suffocating them, Nifa held Petra's arm and said, "Uhm, my name is Nifa and she is Petra. We are looking for a cheap apartment near the university."

The old couple looked at each other with twitched eyebrows. It was as if they were puzzled of what they've heard.

"I think we can help you." The old woman said, a smile painted on her lips. "Right, Captain?"

The old man nodded, his eyes were nailed on Petra's face.

"Let's go?" The old woman said and they walked through the hospital's parking area.

Petra and Nifa were surprised to see a luxurious, olive green matte car. They looked at each other and exchanged a surprised smile. On their way, the old woman asked them why they were looking for an apartment near the university so they told her about their jobs. It didn't take them long to reach their destination until they realized that they were standing before an old manor.

"Where are we?" Petra asked, merely puzzled.

The old man replied, "I thought you two are looking for a cheap apartment?"

"This is an apartment?" Nifa asked, quite amused.

There was a maze-like garden of thorny red roses on the left wing of the frontyard. On the right was a lake with water lilies and a gazebo. The trellis complimented the medieval walls of the manor. The center aisle from the wide gate was leading to a grand staircase going to a wooden double door. It was a big house for two people.

The old woman chuckled. "This is actually our home but we're about to move next week or maybe on Friday so we're looking for someone to live here."

The two ladies looked at each other, bewildered of what they've heard.

"Why don't you check it inside?" The old man offered and started walking up the grand staircase, leaving them behind.

"Come on, ladies." The old woman said and tagged their arms lightly.

As they entered the foyer of the manor, they saw huge paintings framed on the walls and expensive chandeliers were hanging on the medieval designed ceilings. It was old-styled but properly arranged, clean and dust-free. The paintings gave chills to Petra because the illustrations portrayed by the images were gore and bloody. The hues used in the paintings were a contrast of bright and dark perspectives. She thought that the choice of art on the walls was unique.

At first, Nifa wanted to decline the offer out of bewilderment but Petra accepted it because they had no choice. She also didn't want to turn down the old couple's kindness. When they settled the agreement, they learned that they only have to pay for water and electric bills that they'd about to consume; no extra charges.

"You sure about this?" Nifa asked the old couple.

The old woman replied, "We don't want to sell this house because there's so much memories here. And we don't want ghosts to dwell here either."

"Just make sure that every corner of the house is clean, got it?" The grumpy old man told the two ladies.

Petra smiled and with determination, she nodded in agreement. "Yes, sir! We will. Have faith in us."

The couple gave her a surprised stare, then they looked at each other meaningfully. Petra was getting curious as of why they kept on staring at her as if she's done something that has impact on them.

That same day, they moved their entire luggage there and had lunch with the old couple. While enjoying the meal that the old woman had prepared, Nifa asked about the old couple's profession in the past and they learned that the couple was veterans. Petra got interested and asked them about their experiences during the war. The old man told her that he was the captain of the Special Operations Force and his wife was one of his subordinates.

"Ah! Now I understand why you called him Captain." Petra told the old woman. "Amazing."

The old woman gave her husband a meaningful glance and he glanced shortly in return. Petra didn't know why she felt like picturing herself like that of the old woman when she got older. She flashed an admiring smile on her and though she wanted to ask about the old couple's children and grandchildren, she just brushed it out of her mind.


	3. Chapter 2: Part Two

(Part Two)

If there was one thing that Petra couldn't avoid, it's getting attached with people.

It's only been three days and two nights since they started living on the manor, but she felt like finding a home in the city. The veteran couple was very accommodating and generous. She almost treated them as her grandparents. She considered them as a blessing that the deity must have sent. However, the couple arranged all important matters and decided to set their departure on Friday afternoon.

"Where are you going to live now, Grandpa?" Petra asked, curiosity was bothering her since the first day.

The grumpy old man closed the trunk and looked at her. "Somewhere passed the mountains and plains where giants won't hinder our freedom."

She was taken aback. _That's deep._

There was a chuckle coming from the grand staircase. "Don't make fun of her, Captain."

"I just considered not to use the word 'classified'. She's a civilian." He retorted. "Are we all set?"

"Yes." The old woman replied and shifted her attention to Petra. "Don't forget to feed the fishes on my pond, okay?"

Petra nodded. "I sure will, Granny."

"And don't forget to clean the house neatly." The old man reminded.

She chuckled and said, "Okay, got it. Uh, by the way, Nifa should be here."

"The other girl… She went to the hospital a while ago. It's something urgent." The old woman said and held her hands. "I don't know if we can visit you on Holidays so I'm entrusting this home to you. Don't worry, the ghosts here are quite friendly."

She chuckled. "Geez! That's scary."

The old man stood beside his wife and looked at Petra impassively. "If you happen to find an interesting painting, be sure to hang it on the wall. I think someone must have hid one of my collections I couldn't find." He shot a brief glance at the old woman who was grinning secretly.

"Yes, Grandpa." Petra answered with enthusiasm and saluted before him.

"You're giving me chills, kid." He said and reached for her right hand, much to the old woman's smirk that Petra would never understand. "Here, take this with you. It might save you from this cruel world."

Petra shot him a puzzled look before staring at the Swiss knife in her hand; she was stupefied. "W-Why are you giving me a weapon?"

His eyebrows twitched. "Baseball bat is not enough to save your life, young lady."

"You know, he's got a point. I once thought that baseball bat is enough to kill a house intruder. Unfortunately it will only delay his escape strategy. But you'll get the chance to call the police if you threaten him with a Swiss knife." The old woman added.

She nodded, quite enlightened, and bowed her head in front of the couple as an act of gratitude. "Thank you for everything, Granny and Grandpa. I will miss you."

"Aww. Come here." Said the old woman and hugged her tight. "I will miss you too, Petra dear. Tell my regards to Nifa. I hope she's alright."

The old man messed Petra's hair before opening the passenger's door for his wife. "Don't let your guard down, Petra."

Petra's tears welled up while watching the couple's car went off the gate, the old woman was waving a hand from the open window as the car disappeared in her sight. She never expected to have an instant grandparents in the city who would give her a shelter for free. When she went back inside the manor, her eyes scanned the huge paintings hanging on the walls. She remembered when the old man showed her the collection of paintings on the east side of the manor.

 _I don't know where she hid that one painting of a soldier._ He said with twitched eyebrows as they walked through the long corridor of the east wing the other day.

 _Who was that soldier, Grandpa?_ She curiously asked.

He stopped by a certain painting of a female soldier with burnt orange hair and amber eyes. _Her Captain._

The memory made her smile until she remembered to call Nifa.

"Are they still there?" Nifa's voice was a bit groggy on the other line.

"They already left just a while ago. Hey, are you alright?" she asked, there was a hint of worry in her voice.

"I didn't even had the chance to say goodbye." Said Nifa with a frown, "Don't worry about me. I'm fine. I'm on my way back." she added and hanged up.

Their work in the university started two days after the veteran couple left. The manor seemed so empty and lonely but the two ladies managed to adjust some time later.

Petra was usually the one to get up early to prepare their breakfast and get herself fixed. One morning, she accidentally dropped her lipstick on the floor and it rolled under her bed. She let out a muffled complain and crouched down to get it. When she extended her arm to reach for it, she touched an edgy object and got curious.

"What is that supposed to be?" she asked herself and pulled it out from under the bed, her lipstick rolled back to her feet.

Her eyes widen upon seeing a huge painting of a soldier covered by a dusty cloth.

"This must be the painting that Grandpa was talking about… I should tell him! Ugh, I didn't even know where they live now."

She asked Nifa to come over and helped her hang it on the wall of her room just above her bed board.

"You're driving me crazy. How come did you start getting fond of paintings and soldiers?" asked Nifa with a slight scowl on her face.

"Just now." Replied Petra with a smile painted on her face.

Nifa gave her a 'you're getting weird' look.

That night, she stared at the man on the painting for a good two hours. She wondered who it was, still pondering on what the old man told her.

 _Her Captain._

Curious about the painting's whereabouts, she went to the east wing to investigate. She turned on all the lights on the east side of the manor and explored all the paintings hanging on the wall. There were different faces, all of which were wearing combat uniforms, but what's gotten in her mind was the fact that the female soldier with burnt orange hair and amber eyes was the only person painted alone on the canvass. And then there's _Her Captain_ painting in her room which was also another solo.

"Does that make sense?" she asked herself, thinking if her speculation was true.

Three years later, she dreamed of a man called Humanity's Strongest Soldier. He has piercing grey eyes, his face was almost always frowning, and the way he expressed his opinions were blunt it could shut everyone up. She was watching him silently with admiration until he caught her eyes and they made an intimate eye contact. Her heartbeat raced at quite a speed when he started making his way towards her direction.

 _What should I do?_ She asked herself in panic.

He lightly tugged her arm and brought her outside the conference room where all other soldiers where gathered and chatting with each other. She was all surprised, and with wide eyes she stared at him as they walked through the corridors, his hand was still attached to her arm. When they walked pass the right corner of the corridor, he frantically pushed her against the wall and cornered her with one arm.

"Petra." He started, his eyes were piercing through hers. "I don't want to see you hanging out with that brat on your duty."

She was stupefied in her feet. "I…" Words were escaping like as if her mind was now an open prison cell. She couldn't find the words to say.

"I should have let _him_ clean the whole castle the other day. Tch."

 _Castle? Him?_ Petra was so surprised her mouth almost dropped.

There was sudden footsteps coming from the corner so he immediately distant himself from her.

"Levi Heichou!" one of the two men said as if in a hurry.

"What is it, Erd?" he replied. Petra shot him a surprised look.

 _Levi…Heichou…_ she whispered and suddenly woke up soaked in her own sweat.

Her heart was pounding heavily on her chest. "Levi Heichou?" she breathed and turned to look at the painting above her bed board. "Are you a Captain? Is your name… Levi?"

And upon her realization, somewhere in the Survey Corps Headquarters, where titans' remnants and the things for further investigation were lying, slowly appeared a mysterious glass door–the passage between two alternate universe–to reconnect the invisible strings that were never been cut off.

* * *

 **Author's Note: I made some edit on the first two chapters because I suck at writing. But it's alright if you didn't go back reading it. It's just minor edit like I changed the term 'corporal' to 'captain'. And sorry for the long delay. I finally got the chance to update this after almost a year. I hope you're liking this story. I'm expecting reviews so I can know your thoughts about the plot. Thank you. x**


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